Tissue harvesting

ABSTRACT

The present disclosure relates to a tissue collection apparatus. The tissue collection apparatus comprises a housing defining an inlet and an outlet, a first filter disposed within the housing, a second filter disposed within the housing, the second filter configured to isolate tissue particles of a desired size that pass through the first filter under the application of an aspiration force applied through the housing. A method of harvesting tissue is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/058,910, filed Mar. 31, 2008, which claims the benefit of U.S.Provisional Application Nos.: 61/006,662, filed Jan. 25, 2008;61/006,663, filed Jan. 25, 2008; 60/992,210, filed Dec. 4, 2007; and60/909,253, filed on Mar. 30, 2007, and claims priority to GBApplication No. GB0715429.7, filed Aug. 8, 2007, the entire contents ofeach which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to tissue harvesting.

BACKGROUND

Articular cartilage lines the ends of bones and facilitates frictionlessmovement of joints. Damage to the cartilage caused by injury or diseasedoes not heal and the pathological changes resulting from this damagecan be a source of great pain; limiting mobility and having asignificant detrimental impact on the quality of life. Over time,lesions are likely to degenerate into osteoarthritis. Injury is not theonly cause of osteoarthritis, with genetics, obesity, jointbiomechanics, diet and age all playing a role.

Known surgical techniques for treating damaged cartilage comprise lavageand debridement (joint is flushed with fluid and damaged tissue removedproviding temporary symptom relief); microfracture (penetration of thesubchondral bone to stimulate bleeding in to the cartilage lesion in aneffort to promote a fibrocartilage healing response); periosteal grafts(autologous periosteum is grafted into the defect site and sutured orglued into place); mosaicplasty (plugs of cartilage and bone areharvested from low weight bearing regions of the joint and transplantedinto the defect); and autologous chondrocyte implantation (ACI) (cellsare isolated and expanded from a cartilage biopsy from a non-weightbearing location, and the cells are re-introduced into the defect in asecond procedure approximately six weeks later either in suspension oron a scaffold (Matrix-guided ACI-MACI)).

SUMMARY

The tissue harvesting techniques described below can be used to repair,regenerate, and/or augment tissue in a range of surgical or cosmeticapplications.

Trauma to the articular surface is a common injury in sports. Thesymptoms arising from such damage comprise pain, joint locking,instability, and stiffness, and the damage predisposes the cartilage andjoint to wear and degeneration which can lead to osteoarthritis and theneed for total knee replacement. For example, the tissue harvestingtechniques can be used to treat focal and degenerative cartilage lesionsbefore a total joint replacement is indicated and can postpone orobviate the need for a total joint replacement. The techniques enablethe surgical team to purify a unique population of repair cells fromtissue from the patient, such as, for example, synovial/adipose tissue,and deliver the cells back into the patient's joint to stimulate ahyaline-like cartilage repair in a single surgical procedure. The repaircells are harvested arthroscopically from a site local to the defect(i.e. within the joint), the repair cells of a desired range areisolated, for example, by filtering, and the isolated cells are mixed inan unprocessed state (e.g., without further culturing, concentrating,etc.) with a biocompatible gel. The mixture of gel and the isolatedharvested cells is then provided to the repair site.

In implementations of the disclosure the adipose tissue harvested is afat pad or corpus adiposum, which is a localised accumulation ofencapsulated adipose tissue. Fat pads can be found, for example in thecheek (corpus adiposum buccae) and also found within certain jointswhere they are referred to as the infrapatellar, navicular, olecranon,scaphoid, pronator quadratus, and preachilles fat pads. These pads mayact as a cushion to absorb forces generated across the joint and alsomay help to distribute lubricants in the joint cavity.

The infrapatellar fat pad, also referred to as Hoffa's pad and adiposesynovium, comprises synovium and subsynovial adipose tissues and liesbeneath the patella (kneecap) separating it from the femoral condyle.The infrapatellar fat pad varies in size and volume, but generallycomprises two large basal prominences lying on either side of theintrachondylar notch. In situations where forces are directed at thepatella, the infrapatellar fat pad acts as a shock absorber, protectingthe underlying structures. During trauma the infrapatellar fat padundergoes a number of changes, which comprise, without limitation, thefat pad volume increasing secondary to oedema and haemorrhage due toincreased subsynovial vascularisation and the subsequent infiltration ofthe fat pad with macrophages.

We have found that by harvesting a defined size fragment of fat padtissue, comprising progenitor cells, and reintroducing this fragment incombination with a biocompatible scaffold, such as a gel, into anothersite within the body, it is possible to generate tissue types that aredifferent from the tissue fragment following exposure of the fragment toenvironmental factors.

It is envisaged that the progenitor cells contained within the fragmentsof fat pad could be directed along, for instance, the osteogenic,adipogenic, chondrogenic, myogenic, neurogenic lineages giving rise tobone, cartilage, muscle or nerve tissue.

Once the fat pad fragments are implanted into the site, the progenitorcells migrate out of the fragments and integrate into the surroundingtissue, thereby allowing the progenitor cells to differentiate into theappropriate endogenous cell type(s).

The fat pad tissue can be autogeneic tissue, allogeneic tissue,xenogeneic tissue and combinations thereof.

The use of autogeneic tissue is particularly desirable as itsubstantially reduces the potential for an immunogenic host response andtissue rejection.

If autogenic fat pad is to be used, a specific consideration for thesurgeon is how readily accessible the fat pad is during the primarysurgical procedure. For example, if a surgeon is repairing a cartilagedefect within the femoral plateau, then it would be appropriate to usethe infrapatellar fat pad. This will minimise the incisions that thesurgeon has to make and therefore improve the outcome and the welfare ofpatient.

Using autologous tissue as a source for cartilage repair implants isoften limited due to a number of problems including: availability,source, pain and enrichment. The infrapatellar fat pad is a joint tissuethat is easily accessible to the orthopedic surgeon and is present insufficient quantity to load a number of scaffolds for use in cartilagerepair, particularly of focal defects. Furthermore, the use of theinfrapatellar fat pad substantially reduces the possibility of secondarysite morbidity when compared to other tissue sources, such as bonemarrow aspirations, and substantially reduces the need to enrich theprogenitor cells to show therapeutic effect.

In one aspect, the present disclosure relates to an apparatus for tissuecollection comprising:

a housing defining an inlet and an outlet;

a first filter disposed within the housing;

a second filter disposed within the housing, the second filterconfigured to isolate tissue particles of a desired size that passthrough the first filter under the application of an aspiration forceapplied through the housing.

Implementations may comprise one or more of the following features. Forexample, the apparatus further comprises a third filter disposed in thehousing between the first and second filters. The second filter isconfigured to isolate tissue particles of a desired size that passthrough the first and third filters under the application of theaspiration force applied through the housing. The first and secondfilters disposed within the housing define an interior space within thehousing, wherein the apparatus further comprises a port disposed withinthe housing and in fluid-flow communication with the interior spacedefined within the housing. The apparatus further comprises anintroducer configured to comprise a gel. The introducer is configured tobe coupled to the outlet of the housing to introduce the gel into theinterior space of the housing, such that in use, the gel passes throughthe second filter and removes isolated tissue particles collected on thesecond filter, and wherein the gel and isolated tissue particles collectin the interior space of the housing. The apparatus further comprises amixer and a receiver. The mixer and the receiver are configured to bereleasably coupled to the port to receive the gel and isolated tissueparticles from the interior space of the housing. The first filtercomprises a set of pores having a pore size of about 0.6 mm to about 2.4mm, the second filter comprises a set of pores having a pore size ofabout 0.5 mm to about 50 μm, and the third filter comprises a set ofpores having a pore size of about 0.6 mm to about 1 mm. The apparatusfurther comprises a fluid-flow conduit in the interior space of thehousing and in fluid-flow communication with the inlet and the outlet.The apparatus further comprises a second port disposed in the housing.The first port and the second port are in fluid-flow communication withthe conduit. The apparatus further comprises a first valve and a secondvalve, the first and second valves configured to allow for selectivecontrol of fluid flow between the inlet and the outlet and the first andsecond ports. The inlet is in fluid communication with a surgical bladeand the outlet is in fluid communication with an aspiration source.

In an embodiment, the housing comprises a removable lid. The firstfilter is disposed within the lid. The third filter is disposed withinthe lid between the first filter and the second filter. The secondfilter comprises a basket mesh or a substantially frusto-conicalconfiguration. The second filter is releasably coupled to the housing orthe lid. The apparatus further comprises a container shaped to receivethe second filter therein upon removal of the second filter from thehousing.

In another aspect, the present disclosure relates to a method ofharvesting tissue comprising isolating particles of a desired range fromcut tissue aspirated through a tissue cutter, mixing the isolatedparticles in an unprocessed state with a biocompatible gel, andcollecting the mixed particles and gel in an introducer for implantationinto a surgical site.

Implementations may comprise one or more of the following features. Forexample, isolating the particles of a desired range comprises passingthe cut tissue through a first filter and a second filter. The secondfilter comprises openings sized to permit collection of the particles ofthe desired range on the second filter. The method further comprisespassing the biocompatible gel through the second filter to removeisolated particles collected on the second filter prior to mixing theisolated particles with the biocompatible gel. Mixing the isolatedparticles and the gel comprises passing the isolated particles and gelthrough a mixer coupled to the introducer. Mixing the isolated particlesand the gel also comprises placing the second filter with the collectedparticles in a container configured to receive the second filter thereinand introducing the biocompatible gel into the container. The collectingstep comprises aspirating the mixed isolated particles and the gel fromthe container into the introducer. The cut tissue is synovial or adiposetissue. The isolating step comprises collecting particles of the desiredrange in a filter of a tissue collection device solely under theapplication of an aspiration force applied through the tissue collectiondevice to the aspiration lumen of the tissue cutter to aspirate tissuetherethrough.

Advantages may comprise eliminating the risk of disease transmission andimmune response associated with treatment using allograft; enablingcartilage repair procedures to be performed in focal lesions in older aswell as young patients; minimizing damage to the donor site; isolatingtissue fragments which are within a specific size range; minimizingintervention from the surgeon; and harvesting tissue, loading tissuewithin a gel in an expedient manner, and providing the tissue-containinggel for tissue repair in a sterile manner in a single surgicalprocedure.

The details of one or more embodiments of the disclosure are set forthin the accompanying drawings and the description below. Other features,objects, and advantages of the disclosure will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is an illustration of a tissue harvesting assembly shown in use.

FIG. 2 is a cross-sectional view of the surgical blade hub of theassembly of FIG. 1.

FIG. 3 is a perspective view of a tissue collection apparatus of theassembly of FIG. 1.

FIGS. 4a-4d schematically illustrate use of the tissue collectionapparatus of FIG. 3 to isolate tissue particles of a desired size and toprepare a mixture of tissue-containing gel for tissue repair.

FIG. 5 is an illustration of an alternative tissue harvesting assemblyshown in use.

FIG. 6 is a cross-sectional view of a tissue collection apparatus of theassembly of FIG. 5.

FIGS. 7a-7f schematically illustrate use of the tissue collectionapparatus of FIG. 6 to isolate tissue particles of a desired size and toprepare a mixture of tissue-containing gel for tissue repair.

FIG. 8 is an illustration of an alternative implementation of the tissuecollection apparatus of the assembly of FIG. 1.

FIG. 9 is a cross-section view of the tissue collection apparatus ofFIG. 8.

DETAILED DESCRIPTION

Referring to FIG. 1, a tissue harvesting assembly 100 comprises asurgical blade 10 used to cut or resect bodily tissue T, such assynovial or adipose tissue, from a donor site, coupled to a tissuecollection device 40 for isolating cut tissue of a desired sizeaspirated through the surgical blade 10. As discussed below, during thesame surgical procedure, the isolated cut tissue is loaded into, ormixed with, an appropriate carrier, such as a biocompatible gel, andintroduced at a tissue repair site. Preferably, the donor site and therepair site are within the same joint to minimize trauma to the patientand provide for a more expedient surgical procedure.

Surgical blade 10 uses a tube-in-tube construction to shear tissuedisposed between cutting edges of an elongate outer non-rotating tubularmember 12 and an elongate inner rotating tubular member 14, as morefully explained in U.S. Pat. No. 5,871,493, which is incorporated hereinby reference in its entirety. The surgical blade 10 comprises ahandpiece 20 coupled to the tubular members 12, 14 via a hub 22. Theouter tubular member 12 has a proximal end 12 a fixed to the hub 22 anda distal end 12 b defining an opening 15 forming a cutting port orwindow. The inner tubular member 14 is rotatably received in the outertubular member 12 and has a distal end 14 a with a cutting edge (notshown). The inner tubular member 14 defines an aspiration lumen 16 (FIG.2) communicating with the cutting edge to remove cut tissue and fluidfrom a surgical site. When the blade 10 is assembled, the cutting edgeof the inner tubular member 14 is positioned adjacent the opening 15 ofthe outer tubular member 12.

Referring to FIG. 2, the hub 22 (FIG. 1) of the surgical blade 10 iscoupled to the outer tubular member 12 via an opening 41 formed in thehub 22. The inner tubular member 14 is rotatably received within theouter tubular member 12 and defines the aspiration lumen 16 extendinglongitudinally through the inner tubular member 14. The inner tubularmember 14 further defines one or more openings 45 formed through a sidewall 14 b of the member 14 within the hub region of the blade 10, whichare in fluid communication with the aspiration lumen 16 and a chamber 26defined within hub 22. Hub 22 further comprises a side port 24 formedthrough a side wall 28 of hub 22 and in fluid communication with thechamber 26. The side port 24 extends in a direction substantiallytransverse to the longitudinal axis L of the inner tubular member 14.Coupled to the side port 24 is a tubing connector 29. The side port 24provides a pathway for fluid and cut tissue to flow from the surgicalblade 10 to the tissue collection device 40.

Referring to FIGS. 1, 3, and 4A-4D, in addition to the tissue collectiondevice 40, the tissue harvesting assembly 100 comprises an introducer 60(FIGS. 4B-4D) and a mixer 65 (FIGS. 4B-4D). The tissue collection device40 is coupled to the blade 10 via a flexible tubing 50. The tissuecollection device 40 comprises a substantially cylindrical housing 42having an inlet 44 and an outlet 46. The inlet 44 couples the tubing 50to the tissue collection device 40. The outlet 46 is provided to couplethe tissue collection device 40 to a source of vacuum 90 (FIG. 1), suchas a vacuum pump or other suitable apparatus for providing aspirationduring the surgical procedure, via a tubing 52. In addition, acollection apparatus (not shown) can be coupled to the tissue collectiondevice 40 via the tubing 52 to collect tissue and fluid that passesthrough the tissue collection device 40.

Filtration devices, such as disc filters 47, 48, and 49, are positionedwithin the housing 42 with filter 47 disposed closest to or adjacent theinlet 44, filter 49 disposed closest to or adjacent the outlet 46, andfilter 48 disposed between filters 47 and 49. The filters 47, 48, and 49and the housing 42 cooperate to define an interior space 41 within thehousing 42. The housing 42 comprises a port 45 disposed therein, whichis in fluid-flow communication with the interior space 41 of the housing42.

In the implementation shown in FIGS. 1, 3, and 4A-4D, the filter 47comprises a set of pores having a pore size of about 0.6 mm to about 2.4mm, the filter 48 comprises a set of pores having a pore size of about0.6 mm to about 1 mm, and the filter 49 comprises a set of pores havinga pore size of about 0.5 mm to about 50 μm. The filters 47 and 48 filterout larger tissue particles and allow smaller particles to pass through.The filter 49 then filters out particles 71 (FIG. 4B) of a desired sizeand allow particles smaller than the desired size to pass through. Whiletwo filters 47, 48 are shown in this implementation, the tissuecollection device 40 may comprise only one of the filters 47, 48 used inconjunction with the filter 49 to collect tissue particles 71 of adesired size.

The introducer 60 (FIGS. 4B-4D), for example, a syringe, contains asuitable volume (e.g., about 1 ml) of a biocompatible gel 62. Afterparticle collection, the syringe 60 is used to inject the biocompatiblegel 62 into the housing 42 to allow the recovery of the tissue particles71 collected by the filter 49 as will be discussed in more detail below.The mixer 65 (FIGS. 4B-4D), such as a static mixer, is releasablycoupled to the port 45 to receive the gel 62 and isolated tissueparticles 71 from the interior space 41 of the housing and to create amixture 80 of gel 62 and tissue particles 71. A receiver 70 (FIGS.4B-4D) is releasably coupled to the mixer 65 to receive the mixture 80from the mixer 65 and to, for example, provide the mixture 80 to asurgical site.

In operation, as shown in FIGS. 1 and 4A-4D, the surgical blade 10 isbrought into contact with a desired bodily tissue, such as synovial oradipose tissue (FIG. 1). The operator cuts a desired amount of tissuefrom the donor site using the blade 10. The vacuum source 90 aspiratesfluid and the cut tissue through the aspiration lumen 16 of the innertubular member 14 to the tissue collection device 40. During aspirationof the fluid and cut tissue, the port 45 in the housing 42 is closed(FIG. 4A), using, for example, a valve, stop, plug, or other suitabledevice 43. The filter 47 removes undesirable cut tissue from the fluidpathway, such as particles larger than, for example, about 0.6 mm toabout 2.4 mm. After passing through the filter 47, the remainder of thefluid and cut tissue pass through the filter 48, which removesundesirable cut tissue from the fluid pathway, such as particles largerthan, for example, about 0.6 mm to about 1 mm. The remainder of thefluid and cut tissue pass through the filter 49 where tissue particles71 of a desired size, such as particles larger than, for example, about0.5 mm to about 50 μm are isolated and/or retained on the filter 49. Theremainder of the cut tissue and fluid volume pass through the tissuecollection device 40 and are aspirated to the collection apparatus (notshown).

Following aspiration of the fluid and cut tissue, the inlet 44 of thehousing 42 is closed off using, for example, a valve, stop, plug, orother suitable device 43 a, the housing 40 is removed from the tubing50, 52, and the receiver 70 and static mixer 65 are attached to the port45, using, for example, a Luer Lock (not shown) or other suitableconnector (FIG. 4B). The syringe 60 containing the gel 62 is coupled tothe outlet 46, for example, by a Luer lock (not shown) or other suitableconnection. The gel 62 is then injected into the housing 40 and throughthe filter 49 to mix with and expel the tissue particles 71 from thefilter 49 (FIG. 4C). The expelled tissue particles 71 and the gel 62pass through the interior space 41 of the housing 42 and are forcedthrough the port 45 to the mixer 65 (FIG. 4C). The mixer 65 mixes thetissue particles 71 and the gel 62 to promote even distribution of thetissue particles 71 within the gel 62, creating a mixture 80, whichflows into the syringe 70 (FIGS. 4C-4D). Once the desired volume of themixture 80 is collected in the syringe 70, the operator removes thesyringe 70 from the mixer 65 and attaches the plunger 70 a of thesyringe 70 (FIGS. 4c-d ). The operator then applies the mixture 80 at adesired location, such as the surgical site shown in FIG. 1, or themixture 80 can be placed onto a tissue scaffold or used for furtherprocessing.

An alternative implementation of a tissue harvesting assembly 200 isillustrated in FIGS. 5, 6, and 7A-7F. The tissue harvesting assembly 200comprises a tissue collection device 140 and an introducer 160 (FIGS.7E-7F), for example, a syringe, containing a suitable volume (e.g.,about 1 ml) of gel 62. The tissue collection device 140 comprises asubstantially cylindrical housing 142 having an inlet 44 and an outlet46. The housing 142 comprises a lid 143 that is releasably coupled tothe housing 142 using, for example mating threads (not shown), afriction fit, or other suitable connection.

Filtration devices, such as disc filters 147, 148 and a filter 149having a substantially frusto-conical or basket configuration, arepositioned within the housing 142, with filter 147 disposed closest toor adjacent the inlet 44, filter 149 disposed closest to or adjacent theoutlet 46, and filter 148 disposed between filters 147 and 149. Inparticular, the filters 147, 148 are disposed within the lid 143, andthe filter 149 is removably attached to an underside 143 a of the lid143, using, for example, threads (not shown), a friction fit, or othersuitable connection. The housing 140 comprises one or more projectingribs 145 (FIG. 6) disposed about the interior of the cylindrical housing140. The ribs 145 are configured and shaped to receive the filter 149and to releasably hold the filter 149, for example, by a friction fit,within the housing 140.

The filter 147 comprises a set of pores having a pore size of about 0.6mm to about 2.4 mm, the filter 148 comprises a set of pores having apore size of about 0.6 mm to about 1 mm, and the filter 149 comprises aset of pores having a pore size of about 0.5 mm to about 50 μm. Thefilters 147 and 148 filter out larger tissue particles and allow smallerparticles to pass through. The filter 149 then filters out particles 71(FIG. 7B) of a desired size and allow particles smaller than the desiredsize to pass through. While two filters 147, 148 are shown, the tissuecollection device 140 may comprise only one of the filters 147, 148 usedin conjunction with the filter 149 to collect tissue particles 71 of adesired size.

The assembly 200 further comprises a container 170 defining a cavity 170a (FIGS. 7C-7F) configured and shaped to receive the filter 149 in afluid-tight manner therein. An upper portion 170 b of the container 170is configured with threads, or other suitable mating connections, toreceive the lid 143 of the housing 140 as will be described in moredetail below.

The introducer 160 (FIGS. 7E-7F), for example, a syringe, contains asuitable volume (e.g., about 1 ml) of gel 62. The syringe 160 is used tomix the gel 62 with the tissue particles 71 to create a mixture 80within the container 170, and thereafter, to aspirate the mixture 80from the container 170.

In operation, as shown in FIGS. 5 and 7A-7F, the surgical blade 10 isbrought into contact with a desired bodily tissue, such as synovial oradipose tissue (FIG. 5). The operator cuts a desired amount of tissuefrom the donor site using the blade 10. The vacuum source 90 aspiratesfluid and the cut tissue through the aspiration lumen 16 of the innertubular member 14 to the tissue collection device 140. Duringaspiration, the fluid and cut tissue flow through the filter 147, whichremoves undesirable cut tissue from the fluid pathway, such as particleslarger than, for example, about 0.6 mm to about 2.4 mm. After passingthrough the filter 147, the remainder of the fluid and cut tissue passthrough the filter 148, which removes undesirable cut tissue from thefluid pathway, such as particles larger than, for example, about 0.6 mmto about 1 mm. The remainder of the fluid and cut tissue pass throughthe filter 149 where tissue particles 71 (FIG. 7B) of a desired size,such as particles larger than, for example, about 0.5 mm to about 50 μmare isolated and/or retained on the filter 149. The remainder of the cuttissue and fluid volume pass through the tissue collection device 140and are aspirated to the collection apparatus (not shown).

Following aspiration of the fluid and cut tissue, the lid 143, includingthe filters 147, 148, and 149, is removed from the housing 142 (FIG. 7B)and coupled to the upper portion 170 b of the container 170 (FIG.7C-7D). The cavity 170 a receives the filter 149 in a fluid-tightmanner, via, for example, a friction fit, between the filter 149 and thecavity 170 a. Once the filter 149 is positioned in the container 170,the operator removes the lid 143, including the filters 147, 148, fromthe container 170, leaving the filter 149 within the cavity 170 a of thecontainer 170. For example, if the filter 149 is coupled to the lid 143,using a threaded connection and the lid 143 is coupled to the container170 via a threaded connection, the two sets of threaded connections maybe configured such that when the lid 143 is unscrewed from the container170, the filter 149 is unscrewed from the lid 143. Alternatively, if,for example, the filter 149 is coupled to the lid 143 via a frictionfit, then the cavity 170 a of the container 170 is configured to providea sufficient force to retain the filter 149 upon removal of the lid 143from the container.

Once the lid 143 is removed from the container 170, the operator usesthe syringe 160 to inject the gel 62 within the cavity 170 a. The gel 62mixes with the tissue particles 71 to form a mixture 80 of tissue andgel (FIG. 7E). The mixture 80 is then aspirated from the container 170using the syringe 160 (FIG. 7F). Once the desired volume of the mixture80 is collected in the syringe 160, the operator may apply the mixture80 at a desired location, such as the surgical site shown in FIG. 5, orthe mixture 80 can be placed onto a tissue scaffold or used as a feedfor further processing.

In an alternative implementation illustrated in FIGS. 8 and 9, a tissuecollection device 240 comprises a housing 242 having an inlet 244 and anoutlet 246. Positioned within the housing 242 are filters 247 and 249.Filter 247 is disposed adjacent the inlet 244 and filter 249 is disposedadjacent the outlet 246. Extending between the inlet 244 and the outlet246 is a fluid-flow conduit 250 in fluid-flow communication with theinlet 244, the outlet 246 and the filters 247 and 249. The housing 242further comprises ports 252 and 254 in fluid-flow communication with theconduit 250 via conduits 252 a and 254 a, respectively. At theintersections of conduits 250 and 252 a and conduits 250 and 254 a arethree-way valves 256, 258, respectively, that control flow of fluid andtissue or cells between the inlet 244 and the outlet 246, and flow ofgel and a mixture of gel and tissue or cells between the ports 252 and254, as will be described in more detail below.

In the implementation shown in FIGS. 8 and 9, the filter 247 comprises aset of pores having a pore size in the range of about 0.6 mm to about2.4 mm to allow particles smaller than the pore sizes to pass throughthe filter 247 and the filter 249 comprises a set of pores having a poresize of about 50 μm to about 0.5 mm to capture particles larger thanabout 50 μm in the filter 249.

In operation, the operator cuts a desired amount of tissue from a donorsite using the surgical blade 10, as described above, and fluid and cuttissue are aspirated through the tissue collection device 240 via theinlet 244. During aspiration of the fluid and cut tissue, the ports 252and 254 are closed to fluid flow by the three-way valves 256 and 258.The filter 247 removes undesirable cut tissue from the fluid pathway,such as particles in the range of larger than about 0.6 mm to about 2.4mm. After passing through the filter 247, the fluid and cut tissue passthrough the conduit 250 and through the filter 249 where tissueparticles of a desired size, such as particles larger than, for example,about 0.5 mm to about 50 μm are isolated and/or retained on the filter249. The remainder of the cut tissue and fluid volume pass through thetissue collection device 240 and are aspirated to a collection apparatus(not shown).

Following aspiration of the fluid and cut tissue, the inlet 244 of thehousing 242 is closed off to fluid flow and the port 252 is opened tofluid flow using, for example, three-way valve 256. Likewise, the outlet246 of the housing 242 is closed off to fluid flow and the port 254 isopened to fluid flow using, for example, three-way valve 258. Thereceiver 70, and optionally, the static mixer 65, discussed above, canthen be attached to the port 252. The syringe 60 containing the gel 62is then coupled to the port 254 and the gel 62 is injected into thehousing 240 and through the filter 249 to mix with and expel the tissueparticles (not shown) from the filter 249. The expelled tissue particlesand gel 62 pass through the conduit 250 and are forced through the port252 to, for example, the mixer 65 (FIG. 4C) and into the receiver 70 asdescribed above.

In addition to being used in conjunction with the surgical bladeassemblies described above, each of the tissue collection devices 40,140, and 240 can be loaded with biological components by other methods.For example, cell pellets cultured in vitro can be aspirated (e.g. usinga vacuum source) through one of the tissue collection devices 40, 140,240 and then mixed with a biocompatible gel in the manner describedabove.

A number of implementations of the disclosure have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the disclosure. Forexample, while the tissue collection devices 40, 140, 240 have beendescribed as coupled to the blade 10 via a flexible tubing 50, thedevices 40, 140, 240 could be directly coupled to, for example, the port24 of the blade 10 (see FIGS. 1 and 5). In addition, although the tissuecollection devices 40, 140, 240 have been described as includingsubstantially cylindrical housings 42, 142, and 242, respectively,housings 42, 142, and 242 could be any suitable shape. Further, althoughthe syringes 60, 160 have been described as containing a volume of about1 ml of a biocompatible gel 62, the syringes 60, 160 could contain moreor less of the gel 62 depending on the size of the defect to be treated.

In addition, rather than using a static mixer with the tissue collectiondevice 40 to promote a more even distribution of the tissue particles 71in the gel 62, the mixture 80 of gel 62 and tissue particles 71 may berealized solely within the interior space 41 of the housing 42, and thesyringe 70 can be directly coupled to the port 45 to recover the mixture80 directly from the interior space 41 of the housing 42. Further,rather than mixing the gel and tissue in a separate container, such ascontainer 170, the outlet 46 of the tissue collection device 140 can beplugged or otherwise sealed and the mixture 80 of gel 62 and tissueparticles 71 can be realized directly in the tissue collective device140.

Moreover, although the filtration devices have been described as eitherdisk-shaped or basket-shaped filters, other suitable filtration deviceshaving any number of possible geometric shapes may be employed. Suchexamples comprise nucleated cell, microfiltration, tubular, or hollowfiber filtration devices, having, for example, square, cylindrical,tubular, or round geometries. In addition, any filtration surface thatcontacts any of the relevant compositions of the tissue, fluid, or othersurgical materials is sterile or can be readily sterilized.

For the purposes of this disclosure, the injectable gel 62 may compriseany suitable biological or synthetic gels. For example, the gel cancomprise hyaluronic acid, alginate, cross-linked alginate, collagen,fibrin glue, fibrin clot, poly(N-isopropulacrylamide), agarose, chitin,chitosan, cellulose, polysaccharides, poly(oxyalkylene), a copolymer ofpoly(ethylene oxide)-poly(propylene oxide), poly(vinyl alcohol),polyacrylate, Matrigel, or blends thereof.

The apparatuses and systems described herein may be considereddisposable, although they may be reused upon sterilization, such as bygamma irradiation, ethylene oxide, formalin, hydrogen peroxide, orsodium hypochlorite. The filters and syringes discussed herein may becommercially obtained. In particular implementations, the apparatus andcomponents may be plastic, metal, or other suitable material.

Rather than the tubing connector 29 (FIG. 2) being in communication withthe aspiration lumen 16 of the inner tubular member 14 via the chamber26, the tubing connector 29 could be directly coupled to the innertubular member 14. The tubing connector 29 can be coupled to the sideport 24 using any suitable form of connection, including glue, weld,press fit, or, alternatively, the tubing connector 29 can be formed asone piece with the hub 22. The tubing connectors described herein can bemade from plastic, metal, or any other suitable materials.

In addition, although the tissue harvesting assembly has been describedas including a surgical blade 10 used to cut or resect bodily tissue,such as soft tissue, the tissue harvesting assembly can comprise anapparatus containing a curet or burr, for example, to remove bodilytissue, such as bone tissue.

Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A method of harvesting tissue comprising:isolating, between a first filter and a second filter in a tissuecollection device, particles of a desired range from cut tissueaspirated through a tissue cutter; injecting a biocompatible gel intothe tissue collection device such that the biocompatible gel mixes withthe isolated particles in the tissue collection device and is expelledalong with the isolated particles through a port of the tissuecollection device between the first filter and the second filter; andcollecting the mixed particles and the biocompatible gel in anintroducer for implantation into a surgical site, wherein the introduceris removably coupled to the port while collecting the mixed particlesand the biocompatible gel.
 2. The method of claim 1, wherein isolatingthe particles of a desired range comprises passing the cut tissuethrough the first filter and the second filter, the second filtercomprising opening sized to permit collection of the particles of thedesired range on the second filter.
 3. The method of claim 2, furthercomprising passing the biocompatible gel through the second filter toremove isolated particles collected on the second filter prior to mixingthe isolated particles with the biocompatible gel.
 4. The method ofclaim 1, wherein mixing the isolated particles and the biocompatible gelcomprises passing the isolated particles and the biocompatible gelthrough a static mixer coupled to the introducer.
 5. The method of claim1 wherein the cut tissue is synovial or adipose tissue.
 6. The method ofclaim 1 wherein the isolating step comprises collecting particles of thedesired range in a filter of a tissue collection device solely under theapplication of aspiration force applied through the tissue collectiondevice to the aspiration lumen of the tissue cutter to aspirate tissuetherethrough.
 7. The method of claim 1, wherein the introducer comprisesa syringe body having a proximal end configured for receiving a plunger,and a distal end configured for dispensing contents of the syringe, andwherein the proximal end is removably coupled to the port whilecollecting the mixed particles and the biocompatible gel.
 8. The methodof claim 4, wherein the introducer comprises a syringe body having aproximal end configured for receiving a plunger, and a distal endconfigured for dispensing contents of the syringe, wherein the staticmixer is coupled to the port, and wherein the proximal end of thesyringe body is removably coupled to the static mixer while collectingthe mixed particles and the biocompatible gel.
 9. A one-stagearthroscopic surgery method, comprising: removing autologous cartilagetissue from a low weight bearing site by an aspirated tissue cuttingdevice; cutting the harvested autologous cartilage tissue into aplurality of particles as it passes through the cutting device;isolating particles having sizes in a predetermined range of sizes;collecting a mass of the particles between a first filter and a secondfilter in the aspirated tissue cutting device by aspiration in theaspirated tissue cutting device for implantation into a focal cartilagedefect; passing a biocompatible gel through the second filter to removeisolated particles collected on the second filter prior to mixing theisolated particles with the biocompatible gel in the tissue cuttingdevice such that the biocompatible gel mixes with the isolated particlesin the tissue collection device and is expelled along with the isolatedparticles through a port of the tissue collection device between thefirst filter and the second filter; collecting the mixed particles andbiocompatible gel in an introducer, wherein the introducer is removablycoupled to the port while collecting the mixed particles and thebiocompatible gel; and implanting the mass of particles into the focalcartilage defect in the same surgical procedure as the removing of theautologous cartilage tissue.
 10. The method of claim 9, furthercomprising securing the mass of particles in the focal cartilage defectusing fibrin glue.
 11. The method of claim 9, wherein implanting themass of particles into the focal cartilage defect comprises expellingthe mixed particles and the biocompatible gel from the introducer. 12.The method of claim 9, wherein the introducer comprises a syringe bodyhaving a proximal end configured for receiving a plunger, and a distalend configured for dispensing contents of the syringe, and wherein theproximal end is removably coupled to the port while collecting the mixedparticles and the biocompatible gel.